Important Information about Techniques

See Understanding Techniques for WCAG Success Criteria for important information about the usage of these informative techniques and how they relate to the normative WCAG 2.0 success criteria. The Applicability section explains the scope of the technique, and the presence of techniques for a specific technology does not imply that the technology can be used in all situations to create content that meets WCAG 2.0.

User Agent and Assistive Technology Support Notes

Description

The purpose of this technique is to show how table cells in PDF documents
can be marked up so that the logical relationships among rows and columns
are preserved and recognized by assistive technology. This is typically
accomplished by using a tool for authoring PDF.

However, tables converted to PDF may have incorrectly merged or split
table cells, even if they were marked up correctly in the authoring
tool. Authors can ensure that table cells are structured properly by
using the Table Editor in Adobe Acrobat Pro's TouchUp Reading Order
tool.

Examples

Example 1: Repairing table cells using the Table Editor in the TouchUp
Reading Order tool in Adobe Acrobat 9 Pro

This example uses a table that was marked up correctly when it was
created in Microsoft Word. Some table headers span two rows in the
header row; one table header spans two columns.

To check the table in the PDF document:

Advanced > Accessibility > TouchUp Reading Order...

Select the table by clicking the number in the top left hand corner
of the table (3 in the reading order in the image below).

Select the Table Editor button on the TouchUp Reading Order panel.
The table cells will be outlined in red and labeled with their tags.
The red outlines may not exactly match up to the table cells but
you should be able to determine if the cells are tagged correctly.

The following image shows the example table in the TouchUp Reading
Order tool. Note that the Results header appears to span two sub-headers
and the other headers to the left span the two rows in the Results
header.

The following images shows the example table in the Table Editor.
The cells are outlined in red, and the tab for each cell is displayed.
Upon conversion, the Results header was incorrectly split and does
not span its two sub-headers. The headers to the right were incorrectly
split into 2 cells each and do not span the Results headers. In addition,
the incorrectly split cells were merged into one cell.

To repair the Results header:

Select the header in the table (it will be outlined in blue when
selected)

Access the context menu

Select Table Cell Properties...

In the Table Cell Properties dialog, change the Column Span from
1 to 2

Press OK. You'll get a warning that the change might result in
a malformed table structure. In this case, the change is correct.
The cell you changed should change color to show the new span, as
shown in the following image.

Similarly, to repair the incorrectly split header cells to the left
of Results header:

Select the top cell in the column (it will be outlined in blue
when selected)

Access the context menu

Select Table Cell Properties...

In the Table Cell Properties dialog, change the Row Span from
1 to 2

Press OK. The following image shows the correction being made
to the last header cell, with the corrected header cells to its left.

Related Techniques

Tests

Procedure

For a table that has been repaired with the Table Editor, confirm
one of the following:

Read the PDF document with a screen reader, listening to hear
that the tabular information is presented in a way that preserves
logical relationships among the table header and data cells.
(Configure the screen reader to not use heuristics to read table
header cells.)

Using a PDF editor, verify that the appropriate TR, TH,
and TD tags are in the proper reading order and hierarchy
in the table tree.

Use a tool which is capable of showing the table elements
to open the PDF document, view the table structure, and verify
that it contains the appropriate TR, TH, and TD structures.

Use a tool that exposes the document through the accessibility
API, and verify that the table structure contains the appropriate
TR, TH, and TD structures, and that they are in the proper reading
order and hierarchy.

Expected Results

#1 is true.

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.